Motor vehicles increasingly are equipped with windshield-mounted digital camera modules for observing the roadway in front of the vehicle. The camera modules contain a digital imager, as well as a microcomputer for analyzing the digital video signals generated by the imager. Some camera modules include multiple (e.g. stereo) imagers, and perhaps even multiple microcomputers (e.g., a dedicated image processor and a module processor). The camera modules perform various functions including lane departure warning, lane keeping assistance, automatic high beam control, forward crash warning, and traffic sign recognition. Even more sophisticated autonomous vehicle functions will likely be implemented in or with such camera modules in the future.
The camera module is typically mounted to the inside of the vehicle windshield, at a high central location. The location is inside the sweep of the vehicle windshield wipers so that the outer surface of the windshield, at the mounting location, is cleared of rain, snow, and other surface contaminants. Moreover, the camera module will preferably have an air channel for receiving air flows generated by the vehicle defroster, so that any fogging of the inside surface of the window glass at the module mounting location is also cleared.